The present invention relates generally to materials and methods useful for the detection of antibodies; in particular, the invention relates to immunoreagents and immunodiagnostic tests for the detection of pseudorabies antibody in serum samples.
Pseudorabies is an infectious bulbar paralysis also known as mad itch or Aujeszky's disease. Its causitive agent is pseudorabies virus which is a herpes virus suis belonging to the family of Herpesviridae. Pseudorabies is mainly a disease of swine and cattle.
Swine, which is probably the natural host reservoir, infected with pseudorabies often show no symptoms. Infrequently, however, adult swine develop fever and neurological symptoms. Although many infected swine show no symptoms, the virus infection becomes latent and remains for the life of the animal.
In cattle, pseudorabies is a rapidly fatal non-suppurative encephalomyelitis characterized by intense pruritus and self mutilation. Affected cattle generally die within three days of the onset of clinical signs.
Since swine are generally regarded as the natural host and usual reservoir of pseudorabies virus, it is imperative to diagnose psueudorabies in swine before the swine intermingle with cattle. Bovine pseudorabies is prevented only by keeping swine separate from cattle. Although vaccines have been developed which are effective for swine, there is no effective vaccine for cattle.
A serological test for the detection of antibodies to pseudorabies virus is a valuable aid in identifying persistently infected pigs. However, current methods for antibody detection of pseudorabies are time consuming and often not sensitive enough to detect very low levels of antibody. In testing swine, the microtiter neutralization (SVN) test is the commonly employed method (Hill et al, Proceedings of the American Association of Veterinary Laboratory Diagnosis, 20:375-390 (1977)). Significant disadvantage is incurred with the SVN test. The SVN test involves a three to four hour set-up time plus a forty-eight hour incubation time. Another serious drawback of the SVN test is that it involves a biohazard risk associated with the use of infectious virus.
Accordingly, there remains a need for an improved immunodiagnostic test for pseudorabies virus antibody. The present invention provides a safe, reliable, efficient, reproducible and sensitive assay for the detection of serum pseudorabies virus antibody.